Vacuum cleaner



June 10, 1941 J. l. R. BolvlE 2,245,179

VACUUM CLEANER Filed April 1, 1939 Tiarl.

Patented June 10, 1941 2,245,179 i. VACUUM CLEANER Jean Ivan Ragnar Boivie, Stockholm, Sweden, as-

sgnor to Electrolux Corporation, Dover, Del., a 'corporation of Delaware Application'apriu, 1939, serial N0. 265,447

In Germany April 8, 1938 (Cl. 23o-127) 2 Claims.

My invention relates t`o vacuum cleaners and more particularly to an improved centrifugal fan or air pump for use in connection with a vacuum cleaner.

One of the principal objects of my invention is to provide means for reducing the noise produced by the operation of a centrifugal air pump. In fans or pumps of this type there is provided a rotatable impeller consisting of two spaced parallel plates between which are disposed impeller blades. One of these plates is formed with a cen.. trally located air inlet. The air induced through this inlet opening is acted upon by the blades and is discharged at the periphery of the impeller. The impeller is mounted to rotate Within a housing. The housing includes a radially extending wall which is disposed adjacent to the plate of the impeller which is formed with the inlet opening and with as little clearance therebetween* as is possible in order to prevent recirculation back to the inlet of the impeller of the air discharged into the housing at the periphery of the impeller. This wall is formed with an inlet in alignment with the impeller inlet. Another radially extending wall is disposed on the other side of the impeller and is provided with an outlet passage located preferably adjacent to the circumference of the impeller.

Most of the air discharged from the impeller passes directly out through this discharge passage, but tests have conclusively proved that a certain amount of the air immediately upon leaving the impeller ilows in a direction generally opposite to that of the air leaving through the outlet and strikes the wall of thehousing in which the inlet opening is provided. 'I'his results in the production of undesirable noise.

I have determined that, if an enlarged space is provided between the impeller and this wall adjacent to the circumference of the impeller, this noise is materially reduced or substantially eliminated.

Further objects and advantages of my invention will be apparent from the following description considered in connection with the accompanying drawing which forms a part of this specification and of which;

Fig. 1 is a view, partially in cross-section, of a vacuum cleaner embodying my invention, and

Fig. 2 is a view, similar to Fig. 1 but on an enlarged scale showing certain of the parts illustrated in Fig. 1.

Referring to the figures, reference character I designates a hollow casing to one end of which is removably secured a closure member II by imeans of spring clips I2 or-the like. Member II is formed with an opening I3, to which may be connected a hose or other conduit leading from a suction nozzle or the like. Disposed within casing Ill is a dust separating member I4 in the form of a bag made of a materialwhich is impervious with respect to dust, but which permits the passage therethrough of air.

Likewise disposed within casing I0 and supported in any suitable manner is an electric motor I5 on the shaft I6 of which is mounted an impeller designated generally by reference character I1. The impeller includes a hub portion I8 secured to the shaft by' means of a nut I9 or the like. Secured to hub I6 is a circular plate 29 to which is secured a plurality of preferably curved impeller blades 2|. An annular plate 22 is secured to the opposite edges of blades 2I and is thus held in spaced parallel relationship to plate 20. Plate 22 is formed with a centrally located intake opening 23. A

Impeller Il is mounted within a housing 24 which is xed within the casing I0. The housing includes a radially extending Wall 25 which is disposed as close to the plate 22 as is possible. Wall 25 is formed with an intake opening 26 in axially alignment with the intake opening in' Plate 22.

As is apparent especially from Fig. 2, the wall 25 is formed so as to provide an annular recess 2l adjacent to the circumference of the impeller I1. 'Ihe depth of the annular recess 21 in axial direction, designated by reference character a, is approximately one-half of the distance b between the plates 20 and 22 of the impeller. Likewise, the radial distance c from the circumference of the impeller to the radial inner boundary of the recess is also equal to approximately onehalf of the distance b.

The radially extending wall 25 is joined to or integral with a cylindrical axially extending wall which extends behind the fan and is supported by means of a cylindrical member 29 secured to the casing I0. A plate 30 supported by the motor I5 constitutes the rear wall of the fan housing. The outer diameter of this plate is greater than that of the impeller Il but is less than the interior diameter of the wall 28, thus providing an exhaust passage 3|. Member 29 is formed with a radially extending wall 32 which carries a packing 33, the packing contacting the housing of the motor to provide a substantially air-tight seal between the wall 32 and the motor housing. The motor housing is formed with openings 34 at one end and similar openings at the other end wherecool the windings of the motor.

by air may pass through the motor housing to carry guide vanes 35. The end of casing I opposite from closure member Il is provided with a closure member 36 which is formed with an exhaust opening 31.

The operation of the above described device is as follows: Rotation of the shaft I6 and impeller I1 causes air to be drawn in through the intake opening 26 in the wall25 and the opening 23 in the plate I1. This causes a reduction of pressure within the casing I0 and thus air is caused to flow through the inlet openings I3 to the interior of the bag I4, If the opening I3 is connected to a suction nozzle and the latter is passed over a dusty surface, the air will carry with it dust picked up from the surface. 'I'his dust is deposited within the bag Il, While the air passes through the material of the bag to the intake openings 26 and 23.

The air induced into the center of the impeller I'I is acted upon in well known manner by the blades 2| and is discharged at the circumference of the impeller in the direction shown by the arrows in Fig. 2. From these arrows it will be seen that a part of the air so discharged flows directly to the outlet passage 3|. On the other hand, part of the air tends to flow toward the wall 25. However, due to the provision of the annular recess 21 space is provided in which this air may turn and pass to the outlet 3| without impinging strongly against the wall 25. I have determined that this results in a substantial reduction in the noise produced by the operation of the fan. Furthermore, the dimensions of the recess 21 relative to the axial width of the fan, which are given above, appear to give the best results.

The air after passing through passage 3| is deflected by the wall 32 and is caused to flow thereby to the openings 34 in the motor housing. The purpose of the vanes 35 is to eliminate from the air the rotation imparted thereto by the impeller. The air passes through the motor housing, thus cooling the motor windings and is discharged from the cleaner through the exhaust opening 31.

While I have described but a single embodiment of my invention, it is to be understood that this has been done for purposes of illustration only Wall 32 may and thatmodlcations may be made without departing from my invention. For instance, while I have shown but a single impeller, that is a single stage Ian, it is apparent that my invention is equally applicable to a multi-stage fan.

What I claim is:

1. In a centrifugal air pump for a vacuum cleaner, a rotatable impeller including radially disposed spaced parallel plates and impeller blades disposed therebetween, a'housing around said impeller, said housing including a radial wall formed with a central air inlet and disposed parallel and closely adjacent to one ot saidplates and joined to an axially extending cylindrical wall disposed radially beyond said impeller, the space between said radial wall and the adjacent plate being enlarged to form an annular recess opposite the periphery of said adjacent plate, the depth of said recess in the direction normal to said wall being equal to approximately one half the distance between said plates, and a second radial wall adjacent to the otherof said plates, the outer edge of said second wall being disposed radially beyond said impeller but spaced from said cylindrical wall to provide an annular, axially-extending outlet passage opposite to said enlarged space.

2. In a centrifugal air pump for a vacuum cleaner, a rotatableimpeller including radially disposed spaced parallel plates and impeller blades disposed therebetween, a housing around said impeller, said housing including a radial wall formed with a central air inlet and disposed parallel and closely adjacent to one of said plates and joined to an axially extending cylindrical wall disposed radially beyond said impeller, the space between said radial wall and the adjacent plate being enlarged to form an annular recess opposite the periphery of said adjacent plate, the radial distance from the periphery of said adjacent plate to the radially inner boundary of said recess being equal to approximately one half the distance between said plates, and a second radial wall adjacent to the other of said plates, the outer edge of said second wall being disposed radially beyond said impeller but spaced from said cylindrical wall to provide an annular, axially-extending outlet passage opposite to said enlarged space.

JEAN IVAN RAGNAR BOIVIE. 

